1. Field of the Invention
The present invention relates to a multifunction system and a multifunction apparatus.
2. Description of Related Art
Conventional document protection technology disclosed in Japanese Patent Application Publication No. H2-29679 is known that restricts copying of confidential documents and the like printed on paper.
Specifically, Japanese Patent Application Publication No. H2-29679 discloses a copy-deterring sheet having a hidden warning message formed thereon by two types of minute dots, each of which have the same apparent density on the original of the copy-deterring sheet. However, when a user copies the copy-deterring sheet, copying process makes the difference in density between the two types of minute dots larger to render the two types of minute dots distinguishable from each other, so that the warning message formed by the two types of minute dots becomes readily visible on copies made of the copy-deterring sheet, thus deterring unauthorized copying.
Although the warning message appearing on the copies made of the copy-deterring sheet may somewhat deter the user from attempting to copy the copy-deterring sheet, the user can ultimately obtain the copies made of the copy-deterring sheet on which not only the warning message but also confidential information are printed. There raises a problem that the above-described conventional document protection technology merely gives the warning message to the user and cannot stop the user from obtaining copies made of print materials having confidential information and the like.